Railway-traffic-controlling apparatus



Maly 10 1927.

.s. M. LUCAS RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Auz. 27. 1923 7 a a E ii v B A A v A K v T M a m 2 o 0 J 2 l R m w 7 mvsu'roa Patented May 10, 1927,"

i new so .5 rates.

PATENT". oFFicE.

:sAMUEL 1V1; LUCAS, on rzcrrsnunein, :EENNSYLVAN-IA, essrcnon ro THE "UNION swImoH & SlEG'NAL COMPANY, or; swissvenn, PENNSYLVANIA, .A councilman-Ion OF PENNSYLVANIA.

RAILWAY-Tanners.conrRoLLInG APnAnArus.

Application filed A ust-27,1923. Serial No. 659,506.

My invention relates to railway tra tlic controlling apparatus, andparticularly to automatic train control apparatus oi the type comprising train carried governing mechanism controlled by energy received from the trackway. More specifically my invention relates to the traickway portion of such 'ap- 'paratus.

I will describe several forms of apparatus embodying "my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. l is a diagrammatic view showing one form. of trackway apparatus embodying my inven} tion. Fig. 2 is a fragmental View showing a modification of one portion of the-apparatusshown in Fig. 1 and also embodying my invention. V Fig. 3 is a diagrammat c View, similar to 'Fig. 1, b'utshowing a mothfied form of apparatus embodying my n vention.

Similar reference characters refer to similar parts-rineach of the several views.

Referring .first to Fig. 1, the reference characters2 and 2 designate'the track rails of a railway, the rail 2* being divided by insulated joints 3 to form track sections of which only one section, A-B, is shown in the drawing; "Connected across the-rails at one end ofthe section A-B is a source of alternating trackflcircuit current, which, as here shown, is the secondary of a transformer 4, the primary of which isconnected with a transmission line-6. Alternating'current is constantly supplied tothe transmis sion line by .a generator .7. Preferably a resistance 8 is interposed between the secondary ot' transformer 4c and the track rail 2 Located adjacent the other end of the section AB is a track relay R, which, as ie-rein shown, is'iot the. induction motor type, comprisingtwo stator-windings 11 and 12, a rotor 10, and a contact 13 controlled by the rotor. Stator winding 11 is constantly supplied with alteinatingcurrent from the transmission line .6, while stator winding 12 is supplied with. energy from the trackrails of section li -B through the mediaun of .a transformer T having a primary 15, connected across the rails and a.

circuit current supplied "to the rails of section AB by transformer 4.

The track section AB is also supplied with a local alternating train cont-rolling current which is furnishediby a transformer 5, the primary of which is connected with the transmission line 6. In the form shown in Fig. 1 the two terminals'ofthe secondary of transformer!) are connected withthe divided rail-2 atopposit-e endsof the section AB, so that normally the local current flows in the divided rail 2* only. A reactor 9 is interposed between one terminal of transformer 5 and rail 2?.

It is understood that the t-rackway apmratus shown in 1 is intended for cooperation with train carried apparatus which is controlled jointlyby the "track circuitcurrent tromtransformer 4 and by the local currentfrom transformero. It'iis also understood'that in practice the supply of local current from transformer '5 to the section AB will be controlled traflio conditions in advance of this section. The

train carriedap'paratus, and the means for controlling the supply oflocail current, form no part however, 01 my present invention, and, consequently, they are eliminated from the drawing'for the purpose of simplicity. When the apparatus shown in Fig. 1 is in normal condition it will be clear that there is no appreciable difference of potential of local current from transformer '5 across the rails 2 and 2 and so this local current can not aflect thetrack relay B. When .a train l/Voccupies the section A-B, however, if the divided rail 2* should be broken at a point such as21 between the train and the point B, current from the local transformer 5 may flow through wire 20., p'r'imary15 of transformer T, rail 2, andthen through the wheels and axlesof the train W to rail 2 and back to transformer 5. The presence I of'this local current in the primary of transformer T will, o f-course,.produce an induced current in the secondary rloand so in stator winding 1201 relay R. The parts may be so designed that the magnitude of the induced current is not sufiicient to operate the .relay R, so that even in the event-of a train and a broken rail in section 'AB, a dangerous condition would not be created. Certainrelays which are suitable for track relay purposes will respond, however, to the minimum value of local current which can be used for automatic train control, and when a relay of this character is employed it would be necessary to depend upon phase relations of the currents in the stator windings 11 and 12 to prevent false operation of the relay by the local current. These relations are not dependable as a safety factor, however, and, consequently, it is desirable to prevent such false operation in other ways. As shown in Fig. 1, I accomplish this result by providing the core 14 of transformer T with an air gap 17, so that this transformer is of the open magnetic circuit type. The transformer T consequently produces the effect of an impedance in multiple with winding 12 of relay R and so it serves as a shunt which prevents sufficient local current from reaching this winding to operate the relay. The source of track circuit current, however, is of such value as to pass through the transformer T in sufficient quantity to oper ate the relay R.

The apparatus shown in Fig. 1 is particu larly well adapted for use on electric railways of the single rail return type, in which case the track rail 2 serves as the return for the propulsion current.

Referring now to Fig. 2, the transformer between the track rails and the track relay R, which transformer is here designated T, is provided with a closed conductor 18 surrounding a portion of the magnetic circuit, such conductor preferably being of resistance material. A transformer of this character produces the effect of resistance in multiple with the relay winding 12, and this effect may be more desirable in some combinations of relays and track circuits than the effect of an impedance in multiple with the relay winding. The function of the transformer T in Fig. 2 is the same, however, as the transformer T in Fig. 1, in that it serves to shunt from the relay winding 12 such a quantity of the local current that the induced current cannot reach therelay winding in suflicient amount to operate the relay.

Referring now to Fig. 3, the apparatus shown in this view is the same as that shown in Fig. 1, except as to the means for supplying local current to the track rails. In Fig. 3 a resistance 19 is connected across the track rails adjacent one end of the section AB and a similar resistance 19 is connected across the track rails adjacent the other end of the section. The two terminals of the secondary of local transformer 5 are connected with the middle points of these two resistances 19 and 19 respectively, so that the local current flows through the two rails 2 and 2 in multiple. Normally this local current will be balanced in the two rails, so that it will not produce a diflerence eaves? of potential across the primary 15 of trans former T and so it will not influence the track relay R. In the event of sufficient unbalancing of the resistance of the two rails 2 and 2*, however, such as may be caused by a broken rail, local current may flow in the primary of transformer T, and so in the stator winding 12 of relay R. vThe 'air gap 17 in the core of transformer T causes this transformer to act as a reactance in multiple with relay R, however, and so prevents local current from reaching relay R in sufiicientquantity to operate this relay. As in Fig. 1., the track circuit current is of such n'iagnitude as to pass through the transformer T in sufiicient quantity to operate the relay.

Obviously the transformer T shown in Fig. 2 may be substituted for the transformer T in Fig. 3, thereby producing'the effect of a resistance instead of a reactance in multiple with winding, 12. i

The apparatus shown in Fig. 8 is particularly well adapted for steam railroads, and for electric railroads in which both track rails are included in the circuit for the propulsion current. In either case both rails 2 and 2 are divided by insulated joints 3 to form track sections. I 3

One important feature of my invention is that it permits the use of a relay which will respond to a smaller amount of track circuit current than could otherwise be employed. The invention is particularly wellv adapted for the application of train control apparatus to existing railway signaling systems. which systems comprise relays so'designed that they would be falsely operated by a sufficient unbalancing of the local current. By means of my invention it is not necessary to change the relays in such a system,

While the transformers T and T produce the effects-of a reactance and a resistance, respectively, in multiple with the relay wind ing 12, it will he noted that if'either the primary or the secondary circuit of these trans formers should he opened or broken. the relay will be ole-energized, and, consequently, the failure will be on the safe side. On the other hand, if a small reactance or resistance were connected in multiple with the relay winding 12, a breakin such reactance or resistance would not create a failure on the safe side, but, on the contrary, would result in a false energization of the relay in the event of sufficient unhalan'cing of the local current.

Where in the accompanying claims I have used the expression impedance in multi pie with the relay, I mean either the effect of a reactance produced by transformer T or a resistance produced by transformer T Although. I have herein shown and described only three forms of apparatus embodying my invention, it is understood that various changes and modifications may he made therein within-the scope of the appended claims without departing from the spirit and scope of my invention."-

Having thus described my invention what I claim is: V

1. Trackway apparatus for an automatic train controlsystem on arailway of which one track rail is divided to form track sections, comprising a source of alternating track circuit current connected across the railsot a section, a track relay operated by track circuit energy received from the rails said section. a source of alternating local current tions, comprising a source of alternating track circuit current connected across the rails of a section, a track relay operated by track circuit energy received from the rails 01" said section, a source of alternating local current connected with two points in the divided rail of said section and capable under abnormal conditions of causing operation of said track relay, and means interposed between said track rails and said track relay producing the effect oi a reactor in multiple with the relay and thus preventing operation of said track relay by said local current underabnormal conditions.

3. Trackway apparatus for an automatic train control system on a railway of whichone track rail is divided to form track sections, comprising a source of alternating track circuit current connected across the rails of a section, a track relay operated by track circuit energy received from the rails of said section. a source of alternting local current connected with two points in the divided rail of said section and capable under abnormal conditions of causing operation of said track relay, and means interposed be tween said track rails and said track relay producing the effect of an impedance in multiple with the relay and thus preventing operation of said track relav by said local current under abnormal conditions.

4-. Trackway apparatus foran automatic train control system on a railway of which one track rail is divided to form track sections, comprising; a source of alternating track circuit current connected across the rails of a section, a track relay operated by track circuit energy received from the rails of said section. a source of alternating local current connected. with two points in the dithe relay.

vided rail of said; "section, and means interposed between said track rails. and said track relay torpreventing false operation otsaid relay by current from said local source.

5.- Traclrway apparatus for an automatic train control system, comprising a section of track, a source of alternating track cir-v cuit current connected across the rails of said section, atrack relay operated by track circuit energy received from the rails ot said section, a source of alternating local current for said section having the same frequency as said track circuit current and having a value sufficient toifalse ly operate said track relay, and meansinterposed between said= ails and said relay for preventing local current from reaching the relay in sutficient quantity to operate the relay, said source of track circuit current being of such value as to pass through said means in suflicient quantity to operate the relay.

6. Trackway apparatus for an automatic train control system, comprising a section of track, a source of alternating track circuit current connected across the rails of said section, a track relay operated by track circuit energy received from the rails of said section, a source of alternating local current for said section having the same frequency as said track circuit current and hava value suflicient to falsely operate said track relay, and an open magnetic circuit transformer interposed between said rails and said relay for reventing sufficient local current from reac ing the relay to operate the relay, said source of track circuit current being of such value as to passthrough said transformer 1n sufiiclent quantity to operate 7. Trackway apparatus .for an automatic, train control system, comprising a section of track, a source of alternating track circuitcurrent connected across the rails of said section, a track relay operated by track circuit energy received from the rails of said section, a source of alternating local currentfor said section having the same frequency as said track circuit current and having a value suflicient to falsely operate said track relay, and a transformer interposed between said rails and said relay and provided with means for producing the effect of an impedance in multiple with the relay whereby the transformer serves to prevent said local current from reaching the relay in sutlicient quantity to operatethe relay, said source of-track circuit current being of such value as to pass through said transformer in sufiicient quantity to operate the relay.

8. Trackway apparatus for an automatic train control system, comprising a section of track, a source of alternating track circuit current connected across the rails of said section, a track relay operated by track circuit energy received from the rails of said section, means for supplying alternating local current of the same frequency as said track circuit current to the two rails of said section in multiple, and means interposed between said rails and said relay for preventing local current from reaching the relay in sufficient quantity to operate the relay, said source of track circuit current being of such value as to pass through said last mentioned means in suflicient quantity to operate the relay.

9. Trackway apparatus for an automatic train control system, comprising a section of track, a source of alternating track circuit currentconnected across the rails of said section, a track relay operated by track circuit energy received from the rails of said section, means for supplying alternating local current to the two rails of said section in multiple, and a transformer interposed between said rails and said relay and so designed as to produce the efiect of an impedance in multiple with the relay whereby the transformer serves to prevent said local current from reaching the relay in sufficient quantity to operate the relay, said source of track circuit current being of such value as to pass through said transformer in su'tlicient quantity to operate the relay.

In testimony whereof I affix my signature.

SAMUEL M. LUCAS. 

